NVMe: Fix IO for extended metadata formats

This fixes io submit ioctl handling when using extended metadata
formats. When these formats are used, the user provides a single virtually
contiguous buffer containing both the block and metadata interleaved,
so the metadata size needs to be added to the total length and not mapped
as a separate transfer.

The command is also driver generated, so this patch does not enforce
blk-integrity extensions provide the metadata buffer.

Reported-by: Marcin Dziegielewski <[e-mail]>
Signed-off-by: Keith Busch <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/nvme-core.c

···
 	 * stripped/generated by the controller with PRACT=1.
 	 */
 	if (ns && ns->ms && !blk_integrity_rq(req)) {
-		if (!(ns->pi_type && ns->ms == 8)) {
+		if (!(ns->pi_type && ns->ms == 8) &&
+					req->cmd_type != REQ_TYPE_DRV_PRIV) {
 			req->errors = -EFAULT;
 			blk_mq_complete_request(req);
 			return BLK_MQ_RQ_QUEUE_OK;
···
 	meta_len = (io.nblocks + 1) * ns->ms;
 	write = io.opcode & 1;
 
+	if (ns->ext) {
+		length += meta_len;
+		meta_len = 0;
+	}
 	if (meta_len) {
 		if (((io.metadata & 3) || !io.metadata) && !ns->ext)
 			return -EINVAL;
-
-		if (ns->ext) {
-			length += meta_len;
-			meta_len = 0;
-		}
 
 		meta = dma_alloc_coherent(dev->dev, meta_len,
 						&meta_dma, GFP_KERNEL);